In conventional oil and gas well facilities, inhibiting corrosion of the production tubing is necessary in order maximize production and economic return. In present typical commercial situations, approximately twice each month the well is shut down and a corrosion inhibiting chemical is forced down the well under pressure. Such a procedure has been far less than desirable since the loss production time is extremely expensive, though periodic shut-down and corrosion operations are themselves costly and labor-intensive, and the corrosion-inhibiting treatment provided thereby is much less effective than desirable. Usually within several days after a treatment the corrosive effects of gases and liquids from the well reappear. Such corrosion, if improperly dealt with, can cause collapse of the tubing and total loss of the well.
Some of the problems associated with conventional procedures have been addressed by central batch-treating plants, which provide continuous treatment of the production tubing with inhibiting chemical. Typically a stationary, extensive, and expensive plant is built at a location central to a plurality of wells. Conduits are then led from the central plant to each of the wells, and corrosion-inhibiting chemical is continuously injected into the annulus (when a side pocket mandrel is utilized), or down one tubing string of a dual-string well.
According to the present invention, a system and procedure are provided which overcome most of the drawbacks associated with prior systems and procedures. According to the present invention, a production well can be continuously injected with corrosion inhibiting chemical so that collapse of the well will not occur, and there will not be lost production time due to well shut-down for corrosion-inhibiting treatments. The continuous injection according to the invention may be accomplished in a simple and inexpensive manner, and the system according to the invention is feasible for use with each individual production well. According to the present invention the content of corrosion inhibiting chemical is precisely and safely controlled so as to deliver a desired predetermined amount of corrosion inhibiting chemical to the well under all environmental conditions, and in a manner minimizing the risk of explosion, well damage, or operator injury.
According to one aspect of the present invention, a chemical tank, water tank, and delivery and control means are mounted on a portable skid. All of the components when so mounted can be transported on a flat-bed truck/trailer within standard highway weight, length, width, and height limits. The skid, and components thereon, can be easily handled by a small crane, and may be readily moved from one cite to another should that be desired for any reason. All components are conveniently accessible and operation is essentially automatic, and the system according to the invention is relatively inexpensive to construct.
While the system according to the invention is relatively inexpensive and highly portable, it precisely, and automatically, delivers a desired amount of corrosion-inhibiting chemical to the production well. The corrosion inhibiting chemical is injected at the bottom of the well and passes upwardly the entire length of the production tubing. Delivery of the appropriate amount of chemical is accomplished in a safe and efficient manner.
It is the primary object of the present invention to effectively inhibit corrosion of well production tubing in a simple and inexpensive manner. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.